Purpose: To evaluate peripheral vascular endothelial function in patients with normal-tension glaucoma (NTG) and primary open-angle glaucoma (POAG) using noninvasive endothelium-dependent flow-mediated vasodilation (FMD).
Design: Case-control study.
Participants: Thirty patients with NTG, 30 with POAG, and 30 healthy age- and gender-matched controls.
Methods: Participants underwent measurement of FMD and endothelium-independent nitroglycerin-mediated vasodilation (NMD) via high-resolution 2-dimensional ultrasonographic imaging of the brachial artery. All patients also underwent blood sampling for biochemistry, lipid profile, and high sensitivity C-reactive protein analysis.
Main outcome measures: The association of FMD with NTG and POAG.
Results: The FMD values differed significantly between the patients with NTG, those with POAG, and controls: NTG, 2.70+/-2.25%; POAG, 5.33+/-2.81%; controls, 7.21+/-2.36%; P<0.001. In comparison with the POAG group and normal controls, the NTG group demonstrated markedly impaired FMD. The POAG group exhibited higher intermediate FMD than the NTG group (P<0.001) but significantly lower FMD than normal controls (P = 0.012). Multivariate analysis indicated that independent predictors for impaired FMD were presence of NTG, presence of POAG, and advanced age. Additionally, FMD values were significantly lower in glaucoma patients than in controls (4.02+/-2.85% vs. 7.21+/-2.36%; P<0.001).
Conclusions: Patients with glaucoma have impaired FMD. Additionally, patients with NTG have lower FMD than those with POAG.